DESCRIPTION: Weight gain is a common side effect of smoking cessation. It has been estimated that 80 percent of those who quit gain weight, and smokers' concerns about body weight constitute an important deterrent to quitting (Klesges, Meyers, Klesges, & LaVasque, 1989; United States Department of Health and Human Services [US DHHS], 1988). However, estimates of the average postcessation weight gain have varied widely, with mean weight gains ranging across studies from over eighteen pounds to only 0.5 pounds (Klesges et al., 1989). Thus, for at least some smokers, significant weight gains after smoking cessation do not occur. The variability in postcessation weight gain is probably largely attributable to differences in subject variables (e.g., age, precessation smoking rate), methodological factors (e.g., length of follow-up, reliance on self-reports to determine smoking cessation), and treatments (e.g., standard smoking cessation program vs. treatment also targeting weight). However, individual studies of these variables have yielded inconsistent results, making it difficult to interpret the sizeable literature on postcessation weight gain. In such a situation quantitative review procedures can be particularly helpful, in that they provide a systematic method for empirically evaluating the relationship between factors that vary across studies and research results. This FIRST application proposes two such meta-analyses. The specific aims of the first of these are: 1) to identify which types of individuals are most at risk for substantial postcessation weight gain, and 2) to clarify the impact of methodological characteristics on estimates of weight gain. The second meta-analysis will focus on controlled evaluations of treatments designed to reduce postcessation weight gain. Its specific aims are: 3) to evaluate which, if any, treatments are most effective in the prevention of weight gain after smoking cessation, and 4) to determine whether some types of treatments are more effective for specific kinds of patients.